This invention relates to junction boxes. More specifically, this invention relates to weatherproof junction boxes of the type which are intended to be used out of doors and which are structured to permit one or more electrical wires to pass through the box walls into the interior cavity of the box while maintaining the weatherproof integrity of the box.
The increased use of exterior lighting and the desirability of providing permanently installed electrical service exterior to building structures generated a need for the utilization of exteriorly mounted junction boxes.
The initial approach to provision of such junction boxes contemplated the utilization of holes formed in the junction box walls to secure the junction box to a support means. This was found to be unacceptable because the holes in the junction box walls violated the weatherproof integrity of the box, thus giving rise to short circuiting and other undesirable electrical difficulties.
Recognizing this problem, those skilled in the art undertook design activity which was intended to provide functional mounting structures for exterior junction boxes while at the same time preserving the weatherproof integrity of the box. One example of such an approach is found in U.S. Pat. No. 3,197,548 to Weitzman, et al. wherein there is disclosed a junction box having slots formed in the exterior edges which are designed to receive mounting tabs therein. The tabs are provided with bent sections at a 45.degree. angle and, when such bent sections are inserted in the slots, provide outwardly extending tabs suitable for mounting the box on a support structure. Although the Weitzman junction box structure provides for mounting means wherein the weatherproof integrity of the box is retained, those skilled in these arts have found that its basic design is the source of a plurality of difficulties. Not the least of these is that such boxes are manufactured by die casting aluminum and the requirement for slots in the junction box structure presents a need for additional manufacturing steps subsequent to casting, thus increasing the cost of manufacturing and therewith the ultimate cost of the box. Secondly, such slots, particularly in view of the fact that the boxes are manufactured from aluminum, are subject to damage by deformation of the box material which may render the slot incapable of satisfactory use or which requires additional corrective steps at the time of assembly for installation. Such rework also is a source of increased cost. Thirdly, by reason of the fact that the mounting tabs are not secured to the box structure during manufacture, there is the continuing likelihood that the tabs will be inadvertently omitted at the factory, lost during shipment or lost on the job site prior to installation. Anyone who has experienced such loss is aware of the attendant frustration and lost time. Thus, the Weitzman, et al. junction box, while solving one problem gives rise to a number of additional problems which render the design unacceptable to many in this field.
A second and probably more advanced approach to the problem is shown in U.S. Pat. No. 3,187,084 to Stillman, et al. This patent discloses a weatherproof junction box wherein provision is made for securing the box to support structure by the utilization of lug means mounted in channels formed in the exterior surface of the back wall of the box which lugs are secured to the box structure through the use of screws in threaded engagement with tapped bores provided in the box structure. The channels in the back wall of the box are shaped such as to permit reception of the lug means within the basic dimensions of the box so as to accommodate for shipment and storing in the optimum size container. When it is desired to utilize the box at the job site, the mounting screws for the lugs must be loosened, the lugs rotated from stored position to mounting position and the screws thereafter tightened for retaining the lugs in their securing position. The disadvantages of this structure are clear. Initially, the manufacturing operation requires the provision of a plurality of tapped holes each of which requires a machining operation thus adding to the attendant cost of the product. Additionally, with respect to manufacture, the lugs must be assembled by positioning and threadedly engaging the screws within the tapped bores. This also requires a plurality of individual manufacturing operations, all of which add to the cost of the product. Still further, the onsite necessity of unscrewing the lug securing means, rotating each lug into an operating position and thereafter tightening the screws are additional steps in the utilization of the structure which add to overall cost and are thus undesirable.